A bright burst of color made an appearance on the runway of a mostly muted Prabal Gurung show recently. In a sea of grays and blacks, one model stood out in stark contrast — thanks to her daring flame-haired ’do — as she strutted down the catwalk, evoking breathless whispers of “Who’s that girl?” from fashion editors.

“That girl,” it turns out, is 17-year-old Natalie Westling — and she’s setting the fashion world on fire with her stop-sign-hued locks.

Not long ago, the Arizona-born teen was just your average tomboy: a self-proclaimed “anti-girly girl” and an avid skateboarder. But her life changed less than two years ago when she was scouted by the Agency Arizona in Scottsdale, and soon after scooped up by the Society, a New York-based agency that represents high-fashion darlings like Caroline Trentini and Lindsey Wixson, as well as big money girls like Victoria’s Secret Angel Adriana Lima.

Last summer Westling flew to New York to test the Fashion Week waters. She scored just one job, but it happened to be the most prestigious one a model could book — Marc Jacobs. Even more impressive, the booking was what the industry calls an “exclusive” — basically, the fashion equivalent of being crowned prom queen. Westling opened the show, taking a stroll across Jacobs’ dystopian beach before a buzzy cast that included singer Sky Ferreira and models Cara Delevingne and Georgia May Jagger.

For that show, Westling sported dirty auburn blond locks — her natural color — as she did for Louis Vuitton, Saint Laurent and Chanel Haute Couture the same season. The model switched to her now-signature shade of scarlet for Jacobs’ spring 2014 campaign co-starring Miley Cyrus.

“No one else has this hair color, so it would be perfect to keep it,” Westling told the Cut backstage at Prabal Gurung. “It’s so specific, but different.”

Different enough for Gurung at least, as well as Vera Wang, Anna Sui, Marc by Marc Jacobs and mainline Marc Jacobs — all of which are runways the model heated up this past New York Fashion Week, where style insiders became enthralled with her vivid mane and doll-like face.

Models.com put Westling on their “Hot List,” and she’s been compared to fellow It models Chloe Nørgaard and Charlotte Free — currently in vogue for their rainbow-bright locks and cotton candy tresses, respectively. Lucky editor Elana Fishman even likened the model to a young Natasha Lyonne.

Will she become the next Lily Cole or Karen Elson? Only time will tell. Until then, we’ll all be watching this teen beauty bring the new girl heat.